There is a problem with the inline enclosure.
Components inside the inline enclosure don't respond
correctly to call "isVisibleInHierarchy()".
(Returns true even if component is hidden) Attached
is a patch (against wicket 1.4.20) that fixes this.
This patch doesn't fix the problem for components inside nested
inline enclosures. There's a test for this as well, and it fails.
Hopefully this patch might be of help in finding a solution for those as well.